This invention relates to timepiece of the type having a minute hand staff, which in turn drives the hour hand through a speed reducing gear train. More particularly, it relates to an epicyclic speed reducing gear train with means to adjust the position of the hour hand without affecting the setting or timekeeping function performed by the minute hand, while it is still being driven by the driving device of the timepiece.
In a timepiece, it is desirable to be able to change the hour indicated by the hour hand without disturbing the position of the minute hand or affecting the timekeeping of the watch. These changes are necessary when traveling between time zones, or adjusting between standard time and daylight saving time.
There are many types of conventional watch mechanisms for manually correcting the hour hand without disturbing the timekeeping of the watch. Exemplary of these are the following U.S. patents.
U.S. Pat. No. 3,468,122--Lee--Sept. 23, 1969
U.S. Pat. No. 3,693,344--Cleusix--Sept. 26, 1972
U.S. Pat. No. 3,722,027--Challandes--Mar. 27, 1973
U.S. Pat. No. 3,972,178--Beguin--Aug. 3, 1976
U.S. Pat. No. 3,766,730--Kishida--Oct. 23, 1973
Speed reducing gear trains for timepieces have been proposed using epicyclic gearing to provide a 1:12 speed reduction between the hour hand and the minute hand, the following U.S. patents being exemplary:
U.S. Pat. No. 2,036,050--Kenerson--Mar. 31, 1936
U.S. Pat. No. 3,043,089--Sundt--July 10, 1962
U.S. Pat. No. 3,043,090--Sundt--July 10, 1962
However, these proposals do not suggest a mechanism for setting the hour hand unless the minute hand is also set at the same time. It would be desirable to have a simplified speed reduction mechanism for driving the hour hand from the minute hand staff in a timepiece employing a motor to drive the minute hand, which also permits quick and separate setting of the hour hand without disturbing the setting or timekeeping function of the minute hand of the timepiece. Such speed reduction gear train should be suitable for driving with a stepping motor, as used in modern quartz analog wrist watches.
Accordingly, one object of the present invention is to provide an improved quick hour setting system for a timepiece.
Another object of the invention is to provide an improved epicyclic speed reduction gear train for a stepping motor timepiece with provision for quickly setting the hour hand without distrubing the timekeeping function of the timepiece.